An Electric Vehicle Supply Equipment (EVSE) system may be configured to facilitate charging a high voltage (HV) battery or other energy storage element used by electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs) to support various vehicle operations. The EVSE may require a reference voltage or other indication that a vehicle charging system of the vehicle is ready to accept energy from the EVSE. In order to prevent false indications of the readiness of the vehicle charging system to accept energy from the EVSE, a need exists to ensure the EVSE is notified when the vehicle charging system is not ready to accept energy, including during situations in which a controller or other element of the vehicle charging system may be operating improperly.